Humidifier for heated air ducts



Feb. 5, 1952 c. A. WOODRUFF HUMIDIFIER FOR HEATED AIR DUCTS Filed Sept. 8, 1948 2 SHEETS-SHEET l IN V EN TOR. za zwggefl. W

1952 c. A. WOODRUFF 2,584,650

' HUMIDIFIER FOR HEATED AIR DUCTS Filed Sept. 8, 1948 2 SHEETS-SHEET 2 I Z/a zw g ce 0.

Patented Feb. 5, 1952 UNITED STATES PATENT OFFICE HUMIDIFIER FOR HEATED AIR DUCTS Clarence Albert wooarua, Evanston, Ill.

Application September 8, 1948, Serial No. 48,219

air being heated in a hot air furnace for trans- T mission to the rooms of a building of a type that will not only be dependable in operation without constant attention but which will supply the moisture to the air in such a 'manner that it will become entrained therein with no opportunity for any excess water to be precipitated upon the furnace to cause any rusting of the furnace. To this end I have provided a nozzle which, in combination with the target, will produce a fine spray of water deflected into the region of heated air above the furnace; and through the use of certain baflles and shields about the spray, any precipitation of the moisture upon the furnace proper will be prevented.

The baflles and shields, together with the target, prevent any heat radiated from the furnace from reaching thespray nozzle, and the mounting of the nozzle is such that little or no hot air will reach the nozzle by convection. The provisions for keeping the nozzle from becoming heated eliminate one of the most common sources of trouble of a spray nozzle in a furnace-that of the liming up of the nozzle opening due to a precipitation of the dissolved solids in the .water. Most people will be familiar with the liming up or formation of solids in the bottom of a tea kettle, particularly in areas where the water is relatively hard. This is caused by the heat producing a precipitation of the solids carried in the water. Similar dimculties have been experienced in target-type humidifiers. When a liming up of the nozzle of the humidifier appears, it may result in deflection of the water steam to such an extent that a large portion of thesteam does not strike the target but collects upon the furnace, causing rusting and deterioration. If allowed to continue, the nozzle opening maybecom e so obstructed by the solids that little or no water will pass therethrough, and operation of the humidifier is greatly impaired.

To further insure that the humidifier remains in proper operating condition I have provided a mechanism to ream out the nozzle opening upon each operation of the valve controlling the fiow of water through the nozzle. Through this process of reaming out the nozzle, any obstructions that may have become lodged in the nozzle during the last period of flow of water therethrough will become dislodged, and the nozzle will pass water in the desired manner. v

' 3 Claims. ((31.126-113) A further object of the invention is to provide a simple method of regulating the amount of water to be entrained in the air. This adjustment allows the humidifier to be set for proper operation in any size of standard furnace. After the initial installation of the humidifier i made, no further adjustments will be necessary, and there is no opportunity for an unauthorized or accidental change which would produce improper operation of the humidifier.

Additional objects and advantages will become apparent from the following description taken in conjunction with the drawings, in which Fig. 1 is an elevation of a hot air furnace with the humidifier installed thereon and showing diagrammatically the electrical connections for operation of the humidifier;

Fig. 2 is a perspective view of the portion of the humidifier projecting within the furnace bonnet;

Fig. 3 is a sectional elevation of the humidifier installed on the wall of th'e'furnace;

Fig. 4 is a sectional view of the water jet nozzle; and

Fig. 5 is a section taken at line 55' of Fig. 4.

Fig. 1 illustratesa' conventional forced draft, hot air furnace l0, having a riser pipe H to direct the air from the bonnet (that enclosed portion of the furnace surrounding the fire box, ,and'in which the air is heated) to the selected portions of the building to be heated. An air blower I2 is used to force the air through the bonnet, out riser pipe I I and into the building distribution ducts.

Various methods may be employed to control motor l3 of blower [2. The one illustrated chematically in Fig. 1 is suitable for a hand-fired furnace. Wires I4 and I5 lead to a source of electric current, wire l5 being connected directly to the motor through wire I! and wire l4 being connected to one of the normally open contacts of relay I8; The other of the normally open contacts of the relay I8 is connected to the'motor through wire I 9. The coil of relay i8 is energized from transformer 2|, and control is -maintained by building thermostat 22 and bonnet thermostat 23 connected in series withthe sec- 'ondary winding of step down transformer 2| an the coil winding of relay I8.

The contacts in building thermostat 22 are set to close when a pre-determined minimum temperature is reached and are set to open when a pre-determined maximum temperature is reached. Conversely, the contacts in bonnet th'ermostat 23 are set to close when a predeter- 3 mined maximum temperature is reached and are set to open when a predetermined minimum temperature'is reached. Thus when building thermostat 22 calls for heat by closin of the contacts and the furnace is ready to deliver heat by closing of the contacts in bonnet thermostat 23, the coil of relay |8 will be energized, the relay contacts will close, and motor l3 of blower |2 will be .connected to the source of current through wires l4 and I5. When used on automatically-fired furnaces, it is the common practice to use the building thermostat 22 to control the burner operation, and bonnet thermostat 23 v is used alone to control the operation of relay 18.

In applying a target-type humidifier, generally designated 24, to a forced draft, hot air system, it is desirable to supply moisture to the air in the furnace only when blower I2 is in operation. For this reason the electrical energy to operate the humidifier is supplied through wiresr25 and 21, which. connect step-down transformer 28 in parallel with motor 3. In this way the humidifier control circuit will only be energized from wires l4 and I when blower IE is in operation. The secondary of transformer 28 is wired in series with a solenod 29 used to actuate humidi- "fier 24 and a humidostat 3i located in the building that is beingheated. The humidostat is set to close the contacts therein when the moisture content of the air has reached a predetermined minimum and to open the contacts when the moisture content has reached a predetermined maximum. From the foregoing description it will be seen that the humidifier will be actuated when the blower is running and when the humidity of the air in the building hasreached a predetermined minimum amount. If the blower is not running or if the humidity of the air in the building is already sufiicientl'y high, the solenoid 29 will not be energized.

The-humidifier 24 is mounted at, a convenient location on the side of the bonnet of furnace H], with the end of the nozzle 32 and the target 33 projecting within the bonnet. Water is supplied to' the humidifier from water pipe 34 through a) pipe or tube 35 with a water filter 3T interposed between supply pipe 34 and humidifier 24.v The use of filter 3.1'is desirable to prevent any solid material in the pipe 34, such as scale or'rust,

from being received in the humidifier and impairing the operation thereof. If desired, the use or a filter may e simulated.

Solenoid 29 is formed abcut a non-magnetic nection to rod 43 through spring 55.

tube 4|, within which is received an armature 42. Rod 43 is attached to, and projects forwardly from, the armature through an axial opening in the forward end wall 44 of tube 4|. A spring 45 about rod 43 bears against end wall 44 at one end thereof and at the other end thereof against a washer 45 held by a pin 41 on rod 43. The spring serves to hold armature 42 in the position shown in Fig. 3. When solenoid 29 is energized, armature 42 and rod 43 are pulled rearwardly, compressing the spring 45. A water jacket 48 surrounds the actuating rod 43, and water is introduced into the jacket through the connection from pipe 35. At the lower end of the jacketis attached the water jet nozzle 32 having a nozzle opening 5| at the end thereof. At the inner end of the nozzle opening is a tapered valve seat 52 which serves in cooperation with the tapered end 53 of valve closure member 54 to shut off the new cfwater through nozzle opening 5|. A relatively stiff spring 56 is engaged at one an to vaive closure member 54 by inserting the end of the spring in opening 51 in the closure member and at the other end is attached to rod 43 by inserting the end of spring in opening 58 in that rod. One side of valve closure member 54 may be of reduced size where it projects through nozzle 32, as indicated at 59, to allow the free flow of water along the closure member. A plug 60 provides a seal for the rear end of tube 4|.

Atapered prong Bl isconnected to the end of closure member 54 and is adapted to project through nozzle opening 5| when the closure member is in seated position, as shown in Fig. 4. AS solenoid 29, isenergized, rod 43 will be pulled rearw'ardly by armature 42, and closure member 54 will, likewise, be moved by reason of its con- When the solenoid is lie-energized. spring 45 will move rod 43 and closure member 54 forwardly. Thus, each action of the solenoid and valve will run prong 6| through nozzleopening 5|, serving to remove any obstructions that may become lodged in the nozzle opening.

The humidifier mechanism is mounted to a plate 52 by bracket 63 and bolt 64. The plate 62 is, in turn, fastened to the wall of furnace It! by means of self-tapping screws 66. Nozzle 32 projects through plate 62 and the tip of the nozzle is surrounded by a cup shap'edbafflefil having opening 68 in the bottom wall 89 thereof. Opening 58 is of sufiicient size to allow the water jet from nozzle'32to pass therethrough and strike target 33. Bottom wallfiil serves as a deflector to intercept any water from nozzle 32, which is so directed as to not impinge upon target 33. An opening H in the bottom corner of baflie' 5! allows any intercepted water to drained from the baffle.

A drain pan 12, positioned below baflle 57 and target 33, will catch any water draining from these elements, which water will be led outside the furnace into tube 13 and discharged into a convenient drain such as floor drain 14.

Surrounding the baffle and target in the furnace bonnet is a shield formed by semi-circular rings 16 and 11. Ring 16 is attached to plate 52 as by means of welding. Ring surrounds ring [5 andis frictionally engaged thereto. The

"shield will intercept a portion of the water rico 'chetting from target 33, which intercepted water will gr p from the bottom of the shield into drain pan'lll. The amount of the water that 'is inter= cepted by the shield can be variedby adjusting the effective areaof the shield, which adjustment is made by" moving ring T1 toward or away from plate 62. When the humidifier iS' originally in= stalled 'on a furnace, this adjustment is made to insure that there is sufficient heating area in, and air movement'throug'h, the furnace to entrain all thereleased water in the air. If the airwiu take up less water than is being sprayed, the. shield may be extended tointercept more of the water and. return itto'draih 12. If thejfu'rn'aceis "of sufficient capacity to, carry on more water, ring 11 may be moved toward plate 52. thus anowmg more of the water frcmtarget 33' to be sprayed into the r. Once the proper setting has'been made, no further adjustn'ients will be necessary; and because or the fact that -the shield is lo- 'cated on the interior or the bonnet, there is little 73 her which might result-iron a lateral mayor armature 42 and/or rod 43. The allowable tolerances of tube 4|, casing 48, nozzle 32, armature 42, rod 43, and closure 54 are not nearly so critical as they might be if closure member 54 were made an integral part of rod 43.

If it is desired to have the stroke of closure member 54 adjustable, it may be done by threading the inner periphery of tube 4| for a considerable distance forwardly of the rear end thereof. A threaded stop similar to plug 60 is used to engage the internal threads of tube 4! and can be moved longitudinally of the tube to the desired position to limit the extent of the rearward stroke of the armature. A second method of producing the same result would be to make the coil of the solenoid 29 somewhat smaller in length than the length of the casing surrounding the solenoid. By shifting the coil within the casing, the length of the stroke of the armature when the solenoid is energized can be varied.

It should be understood that the particular embodiments of the invention shown in the drawings and herein described are for the purpose of complying with section 4888 of the Revised Statutes and should not be construed as imposing limitations on the appended claims.

I claim:

1. In combination with a heated air duct having an outer side wall, a humidifier mounted on said wall, said humidifier comprising a housing having a nozzle at one end thereof inclined downwardly, said nozzle having an axial water passageway therein provided with a valve seat at the lower end thereof, a plunger mounted in the nozzle for reciprocatory movement therein and having a valve head adapted to cooperate with said valve seat to seal off the lower end of the nozzle, electromagnetic means carried by the housing and operatively associated with the plunger for actuating said plunger to change the position of the valve head with respect to its seat, said side wall having an opening with which the nozzle is operatively associated to move a stream of water downwardly into the air duct when the valve is oiT its seat, and a target mounted within said air duct in the path of the stream ejected from said nozzle to thereby atomize the water and deliver it to the heated air stream, said nozzle being self-draining due to its inclined position.

2. In combination with a heated air duct having an outer side wall, a humidifier mounted on said wall, said humidifier comprising a housing having a nozzle at one end thereof inclined downwardly, said nozzle having an axial water passageway therein provided with a valve seat at the lower end thereof, a plunger mounted in the nozzle for reciprocatory movement therein and having a valve head adapted to cooperate with said valve seat to seal off the lower end of the nozzle, electromagnetic means carried by the housing and operatively. associated with the plunger for actuating said plunger to change the position of the valve head with respect to its seat, said nozzle being shaped to project a stream of water downwardly through an opening in said side wall of the air duct when the valve is oil its seat, a target mounted within said air duct in the path of the stream ejected from said nozzle to thereby atomize the water and deliver it to the heated air stream, said nozzle being selfdraining due to its inclined position and having shielding means associated therewith to protect it from the hot air stream whereby the tendency of the nozzle to be clogged from liming is minimized, and a sump mounted on the interior of said outer wall beneath the target to catch dripings therefrom and to shield the end of the nozzle.

3. In combination with a heated air duct having a side wall, a humidifier mounted on said wall, said humidifier comprising a housing, a nozzle at the lower end of the housing with a water passageway axially therethrough, a plunger in the passageway having a valve associated therewith for opening and closing said passageway, electromagnetic means carried by the housing and operatively associated with the plunger for actuating said plunger, said housing being mounted on said wall in a downwardly inclined position with the nozzle thereof directed to move a stream of water downwardly through an opening in said wall, a target mounted on the inner side of said wall in line with the stream ejected from said nozzle, and a sump mounted on said inner side of the wall beneath said target, said humidifier nozzle being self-draining due to its inclined position.

CLARENCE ALBERT WOODRUFF.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 656,902 Moore Aug. 28, 1900 869,434 I-Ierr Oct. 29, 1907 890,970 Durr June 16, 1908 1,574,856 Armbruster Mar. 2, 1926 1,626,360 Sausen Apr. 26, 1927 1,640,564 Burdick Aug. 30, 1927 2,020,144 Howell Nov. 5, 1935 2,093,444 Hubbard Sept. 21, 1937 2,177,111 Hubbard Oct. 24, 1939 2,187,778 Gardner Jan. 23, 1940 

